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 A279551 Number of length n inversion sequences avoiding the patterns 000, 010, 110, and 120. 22
 1, 1, 2, 4, 10, 27, 79, 247, 816, 2822, 10158, 37875, 145695, 576288, 2337412, 9698820, 41089107, 177424188, 779699793, 3482575169, 15791709187, 72621800171, 338388714955, 1596314968112, 7618218238583, 36756086159343, 179176803145900, 882002961543492 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS A length n inversion sequence e_1e_2...e_n is a sequence of integers where 0 <= e_i <= i-1. The term a(n) counts those length n inversion sequences with no entries e_i, e_j, e_k (where i= e_k. This is the same as the set of length n inversion sequences avoiding 000, 010, 110, and 120. LINKS Megan A. Martinez, Carla D. Savage, Patterns in Inversion Sequences II: Inversion Sequences Avoiding Triples of Relations, arXiv:1609.08106 [math.CO], 2016. EXAMPLE For n=3, the inversion sequences are 001, 002, 011, 012. For n=4, the inversion sequences are 0011, 0012, 0013, 0021, 0022, 0023, 0112, 0113, 0122, 0123. CROSSREFS Cf. A263777, A263778, A263779, A263780, A279552, A279553, A279554, A279555, A279556, A279557, A279558, A279559, A279560, A279561, A279562, A279563, A279564, A279565, A279566, A279567, A279568, A279569, A279570, A279571, A279572, A279573. Sequence in context: A114507 A148105 A127386 * A148106 A291210 A099950 Adjacent sequences:  A279548 A279549 A279550 * A279552 A279553 A279554 KEYWORD nonn AUTHOR Megan A. Martinez, Dec 15 2016 EXTENSIONS Typo in comment corrected and a(10)-a(27) added by Alois P. Heinz, Feb 22 2017 STATUS approved

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Last modified February 22 14:51 EST 2020. Contains 332137 sequences. (Running on oeis4.)